1. Field of the Invention
The present invention generally relates to the field of digital radiography systems, and more particularly to a digital radiography station that can be shared among operatories, each having a dedicated computer, in which image data is automatically routed to the appropriate dedicated computer depending on which operatory is being served by the digital radiography station.
2. Related Art
X-ray radiation has long been employed in the fields of medicine and dentistry to capture images of the human anatomy. Physicians, dentists, and oral surgeons typically use these images to aid in the diagnosis and treatment of conditions and disease, and in the case of dentists and oral surgeons in particular, images of a patient's teeth, mouth, and gums are critical for such purposes.
The most conventional x-ray imaging technique uses radiographic film as the imaging receptor. According to such a technique, a cartridge containing a piece of photographic film is placed in the patient's mouth, for example behind a patient's teeth, and an x-ray beam is projected through the teeth and onto the film. After the film is exposed in this manner, it is developed in a dark room or a closed processor using special chemicals to obtain a photographic image of the tooth.
Solid-state sensors which convert x-rays into an electrical signal have increasingly begun to be used in place of photographic film. Such electronic sensors may include a charge-coupled device (CCD), an active pixel sensor (APS) array, or another type of filmless radiation sensor.
Such digital dental radiography systems offer many advantages over traditional film-based radiography systems. For example, an x-ray sensor is typically more sensitive to x-rays than is film, thereby allowing the x-ray dosage to the patient to be significantly lowered, sometimes by as much as 90% or more. Furthermore, images of the anatomy may be generated by a computer almost instantaneously, thus improving workflow and eliminating the entire film development process, including the use of potentially harmful chemicals. Moreover, because the images are generated electronically, they can be easily stored in and accessed from a computer database.
In digital radiography, the signal from the electronic sensor can be transmitted to the computer or other output device via a long, flexible cable. In other systems, a wireless interface may be used in place of the cable, such that signals are transmitted from the electronic sensor to the computer or output device via a radio-frequency waveform. Wireless communications systems have made inroads into many disciplines and may be preferable in medical and dental digital imaging for a number of reasons. For example, extra wires can be inconvenient for the patient and clinician. Also, in certain diagnostic procedures, the sensor wires may be cumbersome and could limit placement of the sensor with respect to the x-ray tube and computer. In digital dental radiography in particular, such wires can limit sensor placement in the mouth. Furthermore, mechanical failure of the wire can occur due to strain. A wire can also create a trip hazard.
In digital x-ray imaging, the energy source (e.g., the x-ray generator) is typically configured to provide the radiation directly towards the image detector, which is often distant from the source and/or from computer processor components. As discussed above, the image data is often conveyed from the detector using a cable, and in certain applications this cable can be inconvenient for the patient and the operator as it may present various electrical and mechanical constraints. A wireless system, on the other hand, can provide a wider range of degrees of freedom of the detector with respect to the source.
More particularly, in digital dental x-ray imaging, an electronic sensor is placed in the patient's mouth behind the teeth to be examined, and an x-ray beam is projected from an energy source towards the electronic sensor and through the patient's teeth. The x-rays impinge on the electronic sensor, which converts the x-rays into an electrical signal. The electrical signal can be transmitted over a wire to a computer, as described above, and the computer then processes the signal to produce an image on an associated output device such as a monitor or printer. Alternatively, the electrical signal could be transmitted wirelessly from the electronic sensor to a receiver which in turn delivers the signal to the computer.
Communication between the sensor and computer can be effected in various ways. One way is through a commonly available and accessible digital port such as, but not limited to, the Universal Serial Bus (USB). The USB is a serial channel of up to 480 megabits per second (Mpbs) that can be used for peripherals. The USB is a token-based bus; that is, the USB host controller broadcasts tokens on the bus and a device that detects a match on the address in the token responds by either accepting or sending data to the host. The host also manages USB bus power by supporting suspend/resume operations. The USB is advantageous in that it does not require the use of specially designed hardware inside the computer; once the appropriate software has been installed, a peripheral can be plugged into the USB port. In addition, one device can be unplugged and another plugged in without changing the hardware configuration of the computer.
A computer's Peripheral Component Interconnect (PCI) bus and Industry Standard Architecture (ISA) bus also provide a data path between the electronic sensor and the computer's Central Processing Unit (CPU). The PCI bus is an internal 32-bit local bus that runs at 33 MHz and carries data at up to 133 megabytes per second (Mbps), while the ISA bus is an 8- or 16-bit internal bus that carries data at up to 8.33 Mbps. Each of these buses may act as an interface between the sensor and the computer.
A filmless dental radiography system using a USB port, along with an exemplary intra-oral detector, is described in U.S. Pat. No. 6,134,298 to Schick et al., which is hereby incorporated by reference. In Schick et al., the intra-oral detector outputs image data which is received by a computer through its USB port. The system comprises an electronic sensor 1 with connector 1a, a remote board 2 containing the necessary processing circuitry, and a computer 4, the sensor 1 being connected through the computer's USB port. While Schick et al. is well suited for its intended purposes, the interface may not be convenient for certain clinical environments, for reasons that will become apparent.
Dental operatories are often laid out adjacent to each other, and are often configured to share capital equipment in an effort to save cost, among other reasons. For instance, the dental x-ray tube is not typically in continuous use during a patient visit and, as discussed in U.S. Pat. No. 3,922,788 to Rota for example, it may be more cost-effective to share the device between adjacent operatories by moving the device through an opening or pass-through between the operatories. U.S. Pat. No. 4,332,557 to Watanabe, as another example, discusses mounting an x-ray unit such that it may be pivoted and serve adjacent operatories.
The personal computer has become an increasingly important piece of capital equipment in a dental office. It is called upon to serve a variety of tasks, including scheduling and billing as well as patient education, and can form the basis for driving, analyzing, and sharing data from other capital equipment such as digital imaging sensors. The diversity of these tasks often demands that a computer be placed within each and every dental operatory. For instance, while a patient sits in the dental chair, the computer may be used by the practitioner to enter office notes and clinical findings, or as a teaching tool to explain treatment. It can be impractical to share a single computer among the operatories since a particular computer might be in use for a particular patient—for example, might have a patient file open—and switching between patient files can be tedious.
Therefore, while an x-ray tube and digital sensor may be shared among two operatories, it is not as likely that a computer could efficiently be used as a shared resource. As such, the installation of a digital imaging system may require a convenient means of conveying data from a single digital sensor to two separate computers. In a typical installation such as that disclosed in Schick et al, however, the sensor would need to be disconnected from one computer, hand carried to the other, and then reconnected to the second computer. This process can not only be cumbersome, but can also place significant strain upon the electronics interface and computer connectors, which in turn can lead to product failures.
Generally, digital dental imaging detectors operate separate from and asynchronous to the x-ray detector source. Recently, however, detector wiring and circuitry have been integrated with an x-ray source. Such is the case with U.S. Patent Application Publication No. US 2005/0254625 A1 to Schick et al., which is hereby incorporated by reference in its entirety, as if fully set forth herein. There are several advantages to this approach. First, there are fewer components and wires to interfere with the patient and clinician. Furthermore, if a wireless dental sensor is utilized, the radiofrequency receiver can be integrated in close proximity to the patient and in a practical and convenient location, such as inside the x-ray collimator. Moreover, the x-ray trigger signal can be utilized to initiate sensor acquisition.
While this solution is robust, a pass-through configuration, in which an x-ray tube is pivotable through a pass-through so as to allow the device to intermittently serve multiple operatories, still requires a mechanism for automatically conveying the image data from the processing circuitry to the appropriate target computer. Conventional approaches to this problem are unsatisfactory. For example, one standard approach is to use a mechanical A/B switch, in which the practitioner moves the A/B switch into position based on which computer is being used for which operatory. However, mechanical A/B switches are clumsy, aesthetically unpleasing, require manual operation by the practitioner as described, and can be difficult to install seamlessly within a dental or doctor's office.
Given the foregoing, what is needed is a system and method which overcomes the above-mentioned problems and provides a digital x-ray system, shared in a pass-through configuration, which can automatically route image data from the shared digital x-ray system to the appropriate operatory computer.